Even though Apple’s refreshed MacBook Pro models for 2018 feature an iFixit-identified JHL7540 Thunderbolt 3 controller from Intel, unveiled in January as part of the Titan Ridge platform, the notebooks don’t truly support the DisplayPort 1.4 specification.

Intel’s specs sheet clearly states that the new JHL7540 controller provides the same Thunderbolt 3 40 Gb/s performance and feature set as the Alpine Ridge chips while adding DisplayPort 1.4 capability for “increased video performance”.

Older MacBook Pro models released in 2016 and 2017 used Intel’s previous JHL6540 Thunderbolt 3 controller with support for DisplayPort up to version 1.2. As it turns out, support for DisplayPort 1.4 is reliant on built-in graphics, which vary by MacBook Pro model.

Placement of the Thunderbolt 3 controllers on the notebook’s logic board

MacRumors reached out to Apple in an effort to help clear up any confusion customers may have regarding DisplayPort 1.4 compatibility on the new pro notebooks.

Here are your key takeaways.

15-inch MacBook Pro with Touch Bar: These models theoretically support DisplayPort 1.4 at High-Bit Rate 3 (HBR3). Built-in Radeon Pro graphics supports two 5K displays at 60Hz each over a single stream, but the notebooks cannot drive an 8K display.

13-inch MacBook Pro with Touch Bar: Intel’s integrated Iris Plus Graphics 655 GPU does not support DisplayPort 1.4. What you get instead is DisplayPort at High-Bit Rate 2 (HBR2), a signal standard of DisplayPort 1.2.

The publication speculates that the 15-inch models might be able to support 8K displays via VESA’s lossless Display Stream Compression standard, but notes that “it’s unclear if this can be enabled down the road” without updating hardware.

Like theprevious Pros, 2018’s models can drive up to two 5K displays or up to four 4K displays on the 15-inch model, and up to one 5K display or up to two 4K displays on the 13-inch model.

Be sure to read the MacRumors article for more details and kudos to author Joe Rossignol for clearing up the confusion surrounding Apple’s new pro notebooks and DisplayPort 1.4 compatibility.

Apple yesterday confirmed that all four Thunderbolt 3 ports on the new 13-incher are running at full speed. This is an improvement over the older 13-inch models that came outfitted with two full speed ports on the lefthand side and a pair of slower ones on the righthand side.

So, boys and girls, what do you make of the DisplayPort 1.4 situation on the new Pros?